1. Field of the Invention
The present invention relates to a microscope for operation in which an operation within an operated eye is performed by watching an eyepiece in a state of introducing collected illuminating light into the operated eye and illuminating within the operated eye with the collected illuminating light through a front lens which is disposed between the operated eye and an anterior focus position of an objective.
2. Description of Prior Art
Hitherto, there is known a microscope for operation, for example, a stereo microscope apparatus for operation having a configuration as shown in FIG. 1.
In FIG. 1, numeral 1 denotes a pillar, numeral 2 a first arm, numeral 3 a second arm, numeral 4 a X-Y micro-motion device, numeral 5 an operation microscope (referred to, also, as a microscope device), numeral 6 an assistant microscope, numeral 7 a foot switch, and numeral 8 an eye or operated eye. Conventionally, when an operation for the operated eye 8 is performed, an operator causes a contact lens 9 to contact with cornea C of the operated eye 8 as shown in FIG. 2 in an enlarged state.
Next, the operator inserts a light guide 10 for illumination within the eye into the eye and performs the operation by means of an operation instrument 11 such as a cutter, watching an eyepiece in the microscope. Note that in FIG. 2, numeral 12 is crystalline lens of the eye, numeral 13 is vitreous cavity of the eye.
In the conventional microscope for operation, the operator must perform the operation with having the light guide 10 at one hand. Accordingly, it is very difficult to perform a fine operation. So, it is desirable to perform an operation with the operator having operating instruments 11 at both hands (for example, a pair of tweezers at one hand and a cutter at the other hand).
As a result, as shown in FIG. 3, a front lens 15 may be disposed in a front portion of the operated eye 8 between an objective 14 provided in an objective body tube of the microscope and the operated eye 8. An inside of the operated eye 8 is, also, illuminated through the front lens 15.
The microscope for operation having such a construction is preferable to the operator.
However, if the front lens 15 is disposed between the objective 14 and operated eye 8, the following problems are considered.
For example, when a focus distance F of the front lens 15 is too long, since a distance from the eyepiece of the microscope to the operated eye 8 is long, it is difficult for the operator to perform the operation.
On the contrary, when the focus distance F of the front lens 15 is too short, the front lens tends to contact with the operated eye 8.
When the operated eye 8 is, also, washed by physiological saline solution during an operation, there is a problem that the saline solution adheres to the front lens 15 by dispersion of the saline solution.
Furthermore, if the diameter of the front lens 15 is too large, a space between the operation instruments 11 is large by interference of the front lens. In this case, there is an inconvenience that it is difficult to perform an operation with having the operation instruments 11 at both hands. Note that reference numeral 16 denotes one or more inserting parts for inserting the operation instrument(s) 11 into the eye through the part.